• Journal of Digital Convergence
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• v.11 no.11
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• pp.491-498
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• 2013

The purpose of this study was to evaluate the economy and efficiency of two trained athlete groups of different training status. The subjects were 20 elite athletes composed of the cyclists group (n=10) and triathlon group (n=10). All subjects performed steady state testing at 50, 100, and 150 watts, with ample time to reach resting $VO_2$ and ventilation values between stages. The efficiency of two groups appears to be quite different, with triathlon competitors displaying superior efficiency values for the transitions from 0 to 50 and 100 watts. This same principle likely explains the economy of the groups, as triathlon competitor was again more economic at 50 and 100 watts. As though this matching of oxygen consumption and workload they can reduce the amount of oxygen deficit that must be repaid post exercise.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.1026-1034
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• 2012

The purpose of this study was to verify the validation of effect on improvement of muscle strength unbalance according to exercise load deviation during rowing exercise. We performed evaluation of muscular activity and joint torque before the test. We recruited twenty subjects who one side's muscle strength is bigger in more 20% than other side. Subjects divided two groups. One is dominant left side and the other was dominant right side. Subjects performed rowing exercise in electric load deviation rowing equipment (Robo.gym, Humonic Co., Ltd., Daegu, Korea). Exercise performed four sets a day including 25 times a set, and three days a week. Measurements consist of evaluation of muscular activity and joint torque. Exercise load deviation adapted that different value of muscle strength in both arms multiplied 1RM% and added 1RM 50%. The results in adapted load deviation showed that the differences of maximal peak torque in 22.75% were getting increase significantly during exercise in 5.72%. This interpreted that rowing exercise with loading deviation types could provide muscle strength and muscular endurance exercise in same time for balance. Our study found out that loading deviation could provide muscle strength and muscular endurance exercise for improving muscle unbalance.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.4
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• pp.65-70
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• 2010

A small unmanned aerial vehicle(UAV), which uses a propulsion system consisting of electric motor and battery, weighs less than 8 kg, capable of hand launch. Because it is easy to operate and able to transmit image information in real time, the use of small UAV has been increasing. However, very few analysis methods or analysis results on flight performance of the small UAV have been known so far. In this paper, the performance analysis methods of a small UAV, which is manufactured to study an electric powered UAV, are suggested and their results are achieved. Aerodynamic data of the vehicle are obtained by making use of gliding performance from actual flight test, and required thrust and required power by flight speed are predicted. In addition, the methods to predict range and endurance in case of using battery as power source are suggested and their results are achieved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.612-618
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• 2020

In recent years, the demand for external window cleaning has increased, but the process is a very dangerous manpower-dependent operation. In addition, it is difficult to clean at the desired frequency in a business that values cleanliness. Therefore, there is a need to automate this work. This paper presents the concept of a device that can be attached to a specific window and clean the window continuously. The economic feasibility of this device was analyzed. The estimated manufacturing cost of the equipment was approximately 10 million won, but the possible investment cost was at least 9.8 million won for five years of endurance and 103 million won for 10 years of endurance. Therefore, the expected savings well exceed the equipment cost, and it was evaluated as having economic feasibility. Since this study analyzed only quantitative indicators, the expected cost reduction due to a reduction in safety accidents, productivity improvement, construction time reduction, and quality improvement was not considered. Therefore, it is expected that the calculated economic feasibility will be more accurate if the cost reduction effect by the automation equipment is calculated by adding the expected values not considered in this study.

• The Korean Journal of Physiology
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• v.22 no.1
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• pp.63-77
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• 1988

This study was carried out to investigate relationships between maximal running time (MRT) and glycogen supercompensation in fast twitch white fibers (white vastus, WV), fast twitch red fibers (red vastus, RV) and slow twitch red fibers (soleus muscle, SM) of endurance-trained rats. Male rats of a Sprague-Dawley strain were divided into the trained groups and untrained groups. Untrained groups were acquired to run on the treadmill 10 minutes for 3 days and remained rest and maintained with mixed diet for 4 weeks. For last 10 days of resting period, the untrained rats were divided into 3 groups i.e. mixed diet (untrained control), high and low carbohydrate (CHO) diet groups. And each group was subdivided into 2 groups, one group was tested for the MRT and the other was sacrificed to measure the blood glucose, blood lactate, glycogen contents of liver and muscles. The experimental groups were trained on treadmill by a modified method of Constable et al. (1984) maintained with mixed diet for 4 weeks. After measurement of MRT of this group, they were also divided into high and low CHO groups and fed with these diet for 2 days and MRT of each group was measured again to see the effect of high or low CHO feeding on the MRT. Each group was maintained with the same diet for next 2 days during which some of the rats were sacrificed at given time intervals for the measurements of blood glucose and lactate, liver and the muscles glycogen. The results were summarized as follows; 1) In the untrained group, there were no significant differences between subgroups in MRT, glycogen conent of SM, RV and WV. But blood glucose concentration and glycogen content of liver of low CHO group were significantly lower than those of mixed diet group. 2) The MRT and glycogen content of SM, RV and WV of trained mixed diet group were significantly increased compared to those of untrained mixed diet group, but there was no significant difference in glycogen content of liver. 3) MRT of trained mixed, high CHO and low CHO groups were $137{\pm}9.8,\;176{\pm}9.8\;and\;129{\pm}7.3\;min$ respectively with the significant difference between them. 4) There were no differences in blood lactate concentrations between the trained high and low CHO groups immediately after maximal running and during recovery period. 5) Glycogen contents in RV and SM of trained high CHO group were significantly increased, and glycogen contents in RV, WV and liver of trained low CHO group were significantly decreased compared to those of trained mixed diet group. 6) Immediately after maximal running, the blood glucose concentrations of trained high CHO and low CHO groups were $73{\pm}4.0\;and\;67{\pm}6.9mg%$ respecitively. The blood glucose of the trained high CHO group was fully recovered within one hour by feeding. But blood glucose concentration of low CHO group was slowly recovered up to $114{\pm}4.1mg%$ after two hours of feeding and maintained. Those values were still significantly lower than that of trained mixed diet group. The synthetic rates of glycogen in liver and muscles during the recovery period followed the similar time course of the blood glucose recoveries in each group. These results suggest that an increase in MRT of trained high CHO group was attributed to the glycogen supercompensation in slow twitch muscle fibers. And a decrease in MRT of trained low CHO may be due to decreased glycogen contents of liver and muscles. The results also suggest that glycogen supercompensation was more evident in slow twitch red fibers of endurance-trained rats and blood glucose is one of the limiting factors of glycogen synthesis.

• International Journal of Industrial Entomology and Biomaterials
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• v.39 no.1
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• pp.34-38
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• 2019

In this study, we investigated the effect of silkworm, and its by-products on exercise endurance, muscle mass, and fatigue recovery using ICR mice model. Powders of silkworm, pupae, dongchunghacho, and silk powder were suspended in water and feed to mice for 2 weeks. The forced swimming time was increased by 4.3, 4.1 and 2.8 seconds after silkworm, pupae, and dongchughacho administration compared to DW fed group. Increases in exercise ability were achieved by difference mechanism according to feeding materials. Pupae increased muscle mass by 129% compared with the control group which may effect on elongation of swimming time. Dongchunghacho improved the plasma concentrations of fatigue markers such as creatinine, blood urea nitrogen (BUN), and D-lactate. Silkworm administration showed dual effect, the muscle mass induction (114% vs. control) and anti-fatigue (plasma creatinine, BUN, and D-lactate were 63, 75, and 78% vs. con) effect which contributed most elongated swimming time. In conclusion, silkworm and its by-products including pupae and dongchunghacho with the predominant protein and bioactive components improved muscle mass and showed anti-fatigue effect which could promote exercise performance ability.

• PNF and Movement
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• v.10 no.1
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• pp.25-33
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• 2012

Purpose : The purpose of this study was to compare the effect of treadmill training and cognitive task with in the course of treadmill training at the same time with chronic stroke patients. Methods : Fourteen chronic stroke patients participated. Participants were randomly assigned to the control and experimental group(7 experimental, 7 control). All of participants were in-patients at local hospital and had been receiving a traditional rehabilitation program, five days a week. The both groups have undergone 4weeks. The experimental group trained in treadmill and cognitive task at the same time, but control group trained only treadmill. 10m walking test, Timed Up & Go (TUG) test and 6 Minutes walking(6M walking) test to measure the walking speed, dynamic balance and waling endurance ability were carried out before and after the training. Results : The result of the study were as follow:10m walking test were significantly increased both groups(p<.01), but not significant between groups(p>.05). TUG test were significantly increased both groups(p<.001) and between groups(p<.01). 6M walking test were significantly increased both groups(p<.001), but not significant between groups(p>.05). Conclusion : Ahead of return to the community to patients with stroke, cognitive task with in the course of treadmill training at the same time was effective in improving the dynamic balance ability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.618-624
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• 2017

In Seoul and most metropolitan cities, urban trains are delayed due to high congestion during commute times. The delay effect of passengers boarding and disembarking is also significant. In this study, a wide passenger door system was developed as a way to improve the scheduled speed of urban trains by decreasing the passengers' flow time. The door size was defined experimentally to shorten the entrance time. The optimum door size was also determined to improve the stop precision performance of the train while considering the interference effect with peripheral devices. Because the change in door size changes the structural characteristics of the vehicle, the structural stability of a train was analyzed numerically. A prototype of the wide door system was made, and the proposed design was verified using functional and endurance tests. The systematic development process can be used as design data for door size definition and system production when applying a wide door to improve the scheduled speed.

• Journal of International Academy of Physical Therapy Research
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• v.5 no.2
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• pp.743-751
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• 2014

This study aims to identify the effect of home physical therapy on patients who left the hospital after total knee arthroplasty, compared to the Daily living group, when it was applied to them, under the guidance of physical therapists. As research subjects, 20 patients that were scheduled to leave the hospital after unilateral total knee arthroplasty, were chosen, and they were randomly divided into a home physical therapy group(10 patients) and an Daily living group(10 patients) in order to conduct an experiment. During the 4-week research, home physical therapy was offered for 40 mins once for 5 days a week, and muscular strength, gait components were measured. For muscular strength, quadriceps muscle strength, hamstring muscle strength were measured, and as gait components, endurance, speed, step time, single-limb support were analysed. For this experiment, pre- and post-measurement were performed, and collected data were analyzed using SPSS ver. 18.0 statistical program. From the analysis of data, the following study results were obtained. Home physical therapy group and Daily living group both showed significant improvements in quadriceps muscle strength, hamstring muscle strength, and quadriceps muscle strength, hamstring muscle strength of home physical therapy group more significantly improved than Daily living group's. In relation to gait components, gait endurance, gait speed, step time significantly improved in both of home physical therapy group and Daily living group, whereas home physical therapy group only showed significant improvements in single-limp support. According to the comparison between two groups, gait speed, single-limp support and step time improved more significantly in the home physical therapy group than in the Daily living group. In conclusion, positive results were revealed in both home physical therapy group and Daily living group, with regard to muscular recovery of lower limbs of patients discharged from the hospital after total knee arthroplasty and walking, but considering the comparison results between two groups, it seems that applying home physical therapy is more effective than maintaining a daily life.

• Journal of Ginseng Research
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• v.31 no.2
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• pp.93-101
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• 2007

The purpose of this study is to examine the improvement of endurance exercise performance by taking mixtures of Ginseng Radix rubra and Paeonia Radix. For this purpose, time of exhaustion, $V0_2max$, heart rate, and blood lactate was used as improvement index. The experiments were executed to thirty eight men in their twenties. They were randomly assigned into four groups[CG: control group(n=10), IG: ingestion mixtures group(n=9), TPG: ingestion placebo+training group(n=9), TIG: ingestion mixtures+training group(n=10)]. IG and TIG took mixtures of Ginseng Radix rubra and Paeonia Radix for four weeks, and TPG and TIG exercised once a day, three times a week, exercised for 25 minutes during the first week and added 2 minutes by week during four weeks up to 75% of their maximum heart rate. Time of exhaustion showed statistically significant increase for IG, TPG and TIG. TIG had the longest time of exhaustion and IG the shortest. In case of $VO_2max$, no statistically significant change was found among four groups. However, IG, TPG, TIG showed small increase in $VO_2max$. Similarly, no significant change was found for heart rate in rest even though TIG and TPG appear to have decreasing trend. For maximum heart rate, no significant change was found either, but IG, TPG and TIG showed increase. In case of blood lactate from rest to exercise until 18 minutes, no group had significant decrease. In case of blood lactate in exhaustion, IG, TPG and TIG had significant increase. Blood lactate recovery volume at 5 minutes, 10 minutes, 20 minutes showed no significant results for all four groups, but TIG and TPG had a small increase.